Last month I wrote a blog post looking at the drivers for WAN based software defined networks (SDNs). In this blog I’ll take a look at the factors driving data center SDNs. In the same ZK Research / Tech Target survey I referenced in the previous blog, we also asked the question “What capabilities are most important to you in an SDN solution for your data center?”
To my surprise, the top answer (69%) was “Manage the virtual network inside the virtual server stack”. While I’ll agree that managing a network of virtual machines inside a server is a challenge, the problem has largely been solved with a vSwitch. In case you’re not familiar with the role of a vSwitch, I’ll quickly explain it. When traffic is sent from a physical server to another physical sever it travels from server A, down the wire, into a physical switch port, to another switch port, back up another wire and then to server B. Well what if the two servers are now virtualized and on the same physical server? Ethernet doesn’t allow traffic to go down a wire and then back up the same wire – that’s called hair pinning traffic. The solution? The two or more virtual servers would connect to a vSwitch and that would handle the traffic movement.
The vSwitch has now been available for years and is not something I really consider “SDN”, other than it’s a piece of software that has networking capabilities. This is one of the reasons why I still contend users are highly confused as to what an SDN is and isn’t, and what problems to best solve with it. My thoughts are here that many of the people responding to the survey have heard of VMware’s NSX problems — which does far more than connect VMs within a stack — but somehow made the association to their vSwitch.
A close second on the list of preferences in the survey, at 64%, is “ability to implement data center infrastructure on demand”. And the third most popular response was aligned with the second — “orchestrate network provisioning along with servers and storage”. So the combination of these two answers indicates that data center managers are looking to orchestrate and automate the provisioning of data infrastructure. These responses actually attack the two big problems for most organizations when it comes to running a data center: speed of provisioning services and people costs. With a legacy data center, services can often take weeks, or even months, to get turned up because of all the back and forth between the various IT silos. This is one reason why people costs account for 40% of data center TCO today. Automate the provision of the data center stack and you kill two birds with one stone. Interestingly, this is the main value proposition of Cisco’s ACI.
No other response on the survey was above 50%, although improving security posture and policy control was at 49%. Security is a hot issue today across IT — whether it’s SDN, cloud computing, mobility or any other technology — so its strength here isn’t a real surprise.
My take-away from this survey is that it reflects a lot of what I’m hearing in the field and that the battle between VMware and Cisco will soon turn into an all out war with more and more IT individuals aligning themselves with one of these two vendors. We’re certainly at the very early stages of the evolution toward SDN, but the battle lines are starting to be drawn.